1. Field of the Invention
The present invention relates to a portable terminal device having a selective-calling reception (pager) function, and a method for processing a signal received by the portable terminal device, and in particular to improvement in portable terminal operation at a time of reception of a selective-calling message.
2. Description of the Prior Art
Conventionally, a portable terminal device that incorporates a selective-calling receiver is disclosed in, for example, Japanese Unexamined Patent Publication No. Hei 3-64133, and a portable terminal device wherein a selective-calling reception circuit is located in a battery unit is disclosed in Japanese Unexamined Patent Publication No. Hei 6-45986. These portable terminal devices are so designed that a pager radio unit and a pager controller for selective-calling reception, and a portable terminal radio unit and a portable terminal controller for portable radio-telephone terminal transmission and reception are arranged in parallel in the same case. These components independently perform a selective-calling reception function and a transmission/reception function via a portable terminal.
FIG. 1 is a block diagram illustrating such a conventional portable terminal device.
In FIG. 1, a pager radio unit 102 amplifies and demodulates a signal that is received by a pager side antenna 101, converts (decodes) the resultant signal into a digital signal, and outputs it. A pager controller 103 processes the digital signal and performs various control processes. A portable terminal radio unit 202 amplifies and demodulates a signal received by an antenna 201 at a portable terminal side, converts the resultant signal into a digital signal, and outputs it. A portable terminal controller 203 processes a digital signal and performs various control processes. A fast clock generator 204 is commonly used by a pager and a portable terminal device. A communication unit 205 is provided for a portable terminal. A display unit 301 and a key 302 are also provided for a portable terminal device. The pager side antenna 101, the pager radio unit 102 and the pager controller 103 constitute a selective-calling reception unit, and the antenna 201, the portable terminal radio unit 202 and the portable terminal controller 203 constitute a portable terminal unit.
In the selective-calling reception unit of the portable terminal device, the pager radio unit 102 is controlled by a radio unit power source 103a in the pager a controller 103. A digital demodulated signal output by the pager radio unit 102 is synchronized with a reception signal by a pager side synchronizer 103b. A pager ID comparator 103c determines whether or not an ID is included in the reception signal. When the ID is included, the control exercised by the pager radio unit power source 103a is continued, a message that follows the ID is analyzed by a message processor 103d, and the result of the analysis is stored in an information storage unit 103e. When a notification unit 103g is activated by the manipulation of the key 302, a message is obtained from the information storage unit 103e and is displayed on the display unit 301. The processing performed by the selective-calling reception unit is timed by the fast clock generator 204 that is supplied by the portable terminal controller 203.
In the portable terminal unit, the portable terminal radio unit 202 is controlled by a radio unit power source 203a, part of the portable terminal controller 203, and a digital demodulated signal output by the portable terminal radio unit 202 is synchronized with a reception signal by a synchronizer 203b. An ID comparator 203c determines whether or not an ID (differing from that for a pager side) is included in the reception signal. When the ID is included, the control exercised by the radio unit power source 203a is continued, communication data that follows the ID is analyzed by a data processor 203d, display data is stored in the information storage unit 103e, and communication data is converted into analog data by a voice processor 203e and the analog data is output to the communication unit 205. The notification unit 103g on the pager side and the data processor 203d are controlled by a timing controller 203h in consonance with the manipulation of the key 302. Generally, the fast clock generator 204 on the portable terminal side is fast so that it can handle voice data. The communication unit 205 supplies a voice issued by a user of the portable terminal device as a communication data to the voice processor 203e after coding.
Since the conventional portable terminal device as above structured is so designed that the pager side, i.e., the selective-calling receiver, and the portable terminal unit are independently provided and operated, fast processing is performed to employ key input for communication, without any consideration being given to the reception operation performed by the selective-calling receiver. As a result, noise is produced during fast processing and reception by the pager is difficult. In general, the selective-calling receiver employs a low frequency and tends to be adversely affected by the noise.